Field investigation on root diseases.
Research on rubber components in roads. Building of highway from Kuala Lumpur to Klang using rubber as one of the components.
RRIM Headquarters moved to Third Mile, Jalan Ampang, Kuala Lumpur.
Smallholders’ Advisory Service set up in the RRIM.
Early research on crumb rubber.
Enactment to re-constitute RRIM

Studies on latex preservation, rubber lining masterbatch rubber, crepe, Special Processing (SP) rubber and graft polymerization.
Microbiological studies on production of latex concentrates and preservation system.
Research on auxins as latex yield stimulants.

1955

Opening of first Training School for smallholders in Malacca.
Further development in method of yield stimulation.
Early success in NPK fertiliser mixture in trials on inland soils.
Studies on effluent treatment in RRIM Experiment Station, Sungai Buloh.

1960

Refinement of green budding method.
Studies on the distribution of the molecular weight of natural rubber.
Perfecting technical specification of rubber.
First electron microscope in South East Asia commissioned at the RRIM.
Studies on the turgor pressure of the rubber tree laticifer system.

1965

Exploratory research on tissue culture.
Launching of the SMR Scheme.
Promotion of Constant Viscosity (CV)/Low Viscosity (LV) rubber.
Concept of latex vessel plugging in the cessation of latex flow after tapping investigated.
Progress in soil surveys and discriminatory fertilizer recommendations.
Crown budding and experiments on three-part-tree.
Research on the use of ethephon latex flow stimulant.

1970

Promotion of the Environmax concept, where planting recommendation was based on the micro-environment of the planting area.
Promotion of tyre rubber.
Beginning of production of deproteinised natural rubber (DPNR).
Establishment of the Kota Tinggi Experiment Station.
Field planting density studies initiated.

1975

Production of improved DPNR from field latex.
LA-TZ latex introduced.
Research on puncture tapping.
Research on sheep rearing under rubber.
Field trials on “controlled upward tapping” (tapping on high panels).
SMR GP introduced.
Studies on rubberwood utilization ititiated.

1980

RRIM participates in the first gene prospecting expedition to the Amazon. under the auspices of the International Rubber Research and Development Board (IRRDB) .
Research on recombinant DNA (“molecular biology”) initiated.

1985

Launching of young budding to supersede the conventional green budding for clonal propagation of rubber trees.
Improved process for deproteinised natural rubber production introduced.

1990

ROTORRIM developed for the de-ammoniation of skim latex.
RRIM Physical Testing Laboratory is first Malaysian government laboratory to gain accreditation to ISO/IEC Guide 25.
Research on the use of ethylene gas for latex flow stimulation.
“Zero burning” concept of land clearing for replanting rubber promulgated.

1995

RRIM in second Amazon expedition in collaboration with Brazil.
RRIM appointed the Standards Writing Organisation for the development of Malaysian standards for rubber and rubber products.
Standard Malaysian Glove Scheme launched.
RRIM 2000 series latex timber clones released.
RRIM's transgenic rubber plants produce a functional recombinant latex enzyme.
RRIM merges with MRRDB and MRELB to form Malaysian Rubber Board.

2000

Joint base-isolated demonstration building in Sabah with PORIM, using rubber seismic bearings.

The Story of Malaysian Natural Rubber

How the rubber industry began

Of all the wonderful tales brought back by Christopher Columbus in 1496 after his second voyage to the New World, none was stranger than the tale of a ball, which bounced. The people of Haiti made these playballs from the gum of a tree.

Although they did not realise it, Columbus and his crew were the first Europeans to see this unique substance – rubber. It did not get its name until much later – in 1770, an eminent English chemist, Joseph Priestley, noted the ability of this substance to ‘rub out’ pencil marks, and ever since it has been called rubber in the English language. This is curious, because ‘rubbing out’ has never been an important use of rubber.

In spite of the interest it aroused very little use was made of the new discovery. This was mainly because no one knew how to prevent the rubber becoming sticky in summer and brittle in winter.

In the early nineteenth century, all this changed. In 1820, Thomas Hancock, an Englishman invented a machine, which would soften, mix and shape rubber. It was then possible to dissolve rubber and start making useful products. By coating cloth with the rubber solution it could be made waterproof; the first ‘Mackintosh’ was made in 1823. Soon after there was another important discovery, this time by an American. In 1839, Charles Goodyear found by accident that raw rubber could be improved by heating it with sulphur. The new material produced, called vulcanized rubber, was no longer affected by changes in temperature.

As other inventors found uses for rubber the demand grew. Some of the first products to be made from rubber were hose, conveyor belts, flooring and footwear – these still use rubber today. In the middle of the nineteenth century rubber came from South America, where the hot wet climate suited the wild rubber tree, but it was very difficult to collect it from the dense jungle. It soon became obvious that more rubber would have to be grown elsewhere to meet the demand.

In 1876, Sir Henry Wickham, at the request of the India Office, collected and shipped from Brazil 70,000 seeds from the wild rubber tree. These were rushed to Kew Gardens in London and planted in specially prepared hot-houses. The small number, which survived, were taken in 1877 to Ceylon and later to Malaysia and other countries of South-east Asia.

The rubber tree quickly flourished in Malaysia; large areas of jungle were cut down and planted with rubber trees. Henry Nicholas Ridley, who was appointed Director of the Singapore botanic gardens in 1888, was one of the pioneers of those times and did perhaps more than anybody to encourage planting of this new crop.

By the end of the nineteenth century there were 2500 hectares of rubber in Asia. Shortly afterwards Henry Ford started making his famous motorcar and the demand for rubber – to make tyres – rocketed. The trees in the South American jungle could not possibly produce enough rubber and so the new plantations of Asia found that the world wanted all the rubber they could produce, and more. By 1910 there were ½ million hectares of rubber planted and the countries of Asia had now become the main suppliers of rubber.

With the spread of motoring to every country in the world, even today’s enormous acreage of rubber (about 6 million hectares in all) cannot supply enough. There is not enough natural rubber to go around. Scientists have developed man-made rubbers from petroleum. These are often mixed with natural rubber. For some products, however, only natural rubber can be used.

More rubber from better trees

Peninsular Malaysia – comprising 12 of the 14 states in the Malaysian federation – is among the world’s most important rubber growing areas. Rubber is also grown in Sabah (formerly North Borneo) and Sarawak, which, known together as East Malaysia make up Malaysia.

Altogether Malaysia produces almost 20% of the world’s natural rubber. A good deal of Malaysia’s rubber (over half) comes from thousands of privately owned plots of land called smallholdings, which are usually about 2 hectares. The rest is grown on big estates owned by various companies; each can cover over a thousand hectares. Altogether, Malaysia has 1.7 million hectares of rubber.

In recent years most of the older trees have been replaced by newer varieties which yield up to ten times as much rubber, thanks to scientific cross-breeding and careful cultivation.

If you were a rubber tapper you would have to get up very early in the morning, as the rubber latex flows more easily before the heat of the day begins. Latex is a milk-like fluid contained in tiny cells situated beneath the outer bark of the rubber tree. The latex is obtained from the tree by tapping that is cutting away a thin shaving of the bark about 2 mm thick. This cut, which is made with a special tapping knife, pierces the cells and the latex oozes slowly out to a collecting cup placed below. The tapper needs great skill with his knife as the tree is easily damaged if the bark is cut too deeply.

In two or three hours the flow of latex ceases. By the time the tapper has cut his last tree for the day the latex collecting cup of the first is ready to be emptied into a larger container. When all the cups have been emptied the full containers are taken to the factory, where the latex is turned into raw rubber.

Rubber trees are not tapped until about five years after planting; by then they can produce enough rubber to make tapping worthwhile.

If you were working on your own smallholding you would probably take your latex to a group processing centre to process the latex into sheets or sell it to Mardec, a government agency which processes rubber into technically specified form. The big estates have their own machines. After processing it is sent to one of Malaysia’s ports to be shipped overseas. Malaysian rubber goes to every country in the world and is recognised to be the best.

Rubber in industry and the home

Rubber is elastic, flexible, airtight, watertight, long lasting and insulating, to mention just a few of its properties. There are thousands of products, which take advantage of these useful properties. Some will be familiar to you, others less so because many rubber products do their work unseen.

Most of the world’s rubber is used in tyres, ever since John Boyd Dunlop invented the pneumatic tyre in 1888. A tyre is not just a hunk of rubber, it is skillfully designed to do its job and it is made, not only of rubber, but also of other materials; fibres, steel and various chemicals. Some tyres use man-made rubber but for the toughest kinds of tyre only natural rubber will do. Aircraft tyres are a good example; these have to take tremendous punishment during landings and take-offs. They get very hot, hotter than boiling water, and natural rubber is always used to stand up to these conditions. The same is true for giant lorry tyres. The tyres on your family car have an easier life and they will have a lot of man- made rubber in them but they will also use some natural rubber in those parts of the tyre where it is needed.

As well as tyres, modern cars and lorries use a lot of rubber in other ways. Engines are mounted on rubber to cut down vibration. Some lorries and cars have rubber springs instead of steel ones. Then there are radiator hoses, windscreen wiper blades, car mats, seals and all sorts of small components such as bushes and gaskets hidden away under the bonnet or in the suspension.

Many motorway bridges are mounted on large blocks of natural rubber to allow the bridge to expand and contract when the temperature goes up or down. Some buildings are now built on similar rubber blocks to help stop vibration, particularly if they are near railways. In this and many other ways rubber helps to make life quieter and more comfortable.

Throughout the industry, rubber does all kinds of different jobs. Hose to carry liquids; conveyor belts to carry coal, gravel, ores; seals for machinery and so on. The list is endless.

In everyday life you make more use of rubber than you perhaps realise. Did you know that the adhesive on transparent sticky tape is made of rubber? More obvious, many sports balls are made of rubber and the carpets and rugs in your home may have a foam rubber backing underneath. Your shoes may have rubber soles, and, if you travel on London’s underground, you may like to know that the escalator handrail is made of rubber and the trains have rubber springs.

Role of the The Malaysian Rubber Board in R & D

Introduction

Natural rubber in the true sense is a science-based material, for it would not be commercially viable without the input of a considerable technical effort over many years. The application of agricultural science (plant breeding, physiology, disease control, etc) has raised the productivity ten times over that of the original importations of Hevea. Research into the processing, properties and application of NR has helped the industry to maintain its supremacy in the family of rubbers. Malaysia has been a leader in technical progress since the industry started in the early years of the century. The industry provides millions of ringgit annually to carry out such R&D activities. The money is collected through a research cess of 3.85 sen for every kilogram of rubber exported. It is used to finance research spearheaded by the Malaysian Rubber Board (MRB).

MRB is a government agency under the aegis of the Ministry of Plantation Industries and Commodities (KPPK) established with the specific purpose of exercising overall control of the research, technical development, market regulation and promotion work in support of the Malaysian rubber industry. Although most of the industry is in the hands of the private sector – either as estates or as smallholdings – the health and vitality of this commodity is of prime importance to the government. The MRB’s basic role is to assist the Ministry of Primary Industries in its planning to ensure the future viability of this industry. Execution of the plan lies with a number of agencies, namely RISDA, MARDEC and FELDA while the MRB itself determines policies and executes programmes of research, development, promotion, licensing and regulation and provides the necessary funds in pursuit of its activities and functions of its operation units viz the Rubber Research Institute of Malaysia (RRIM) and Tun Abdul Razak Research Centre (TARRC).

The responsibilities of the MRB are wide-ranging and include all aspects of the rubber industry from production to end-usage. However, two main objectives are involved: first, to promote and develop the rubber industry of Malaysia, and secondly, to develop national policies and priorities for the orderly development of the rubber industry of Malaysia.The structure of MRB has been streamlined to allow these objectives to be carried out effectively. Production research is centred in RRIM; developments and innovations resulting in higher productivity and better product and processes are disseminated through MRB’s own extension services; and end-use research facilities are located both in the West (in TARRC) and at RRIM’s Technology Centre in Sungai Buloh, Selangor.

R&D Contributions

Increased productivity

Breeding and selection provides one of the most fundamental approaches to modernisation of the industry. The breeding and selection of high yielding cultivars and new methods of propagation, planting and exploitation are carried out extensively at the 1500 hectare RRIM Experiment Station. The aim of breeding and selection is to continually upgrade planting materials until the theoretical limit is approached. New genetic materials, collected from the Brazilian forests in 1981, will enable plant breeders to evaluate new clones from the now larger gene pool.

The most significant achievement has been in developing new rubber varieties or clones. High-yielding trees producing more than 3,500 kg per hectare per year and disease-resistant clones have been developed by RRIM. In addition, remarkable progress has been achieved in reducing the immaturity period from 96 to 54 months. Plantations throughout the country as well as rubber producing nations have also adopted agro-management practice developed by RRIM. Work on soil conservation and soil fertility has helped to restore ecological balance and greening of barren land including enriching the soil.

Research in the mechanisation of rubber production and collection has been given much attention. Low Intensity Tapping Systems (LITS) are technologies promoted by RRIM to tackle the acute labour shortage problem. The LIT Systems consist of three technologies, i.e. LIT d/6; RRIMFLOW and REACTORRIM.

RRIM is also giving priority to develop timber-latex clones to cope up with increasing demand for wood as well as latex.

Strategic research

Genetic engineering and biotechnology have proved resourceful in plant breeding, especially in the production of transgenic plants that could produce valuable pharmaceuticals and certain types of latex.

Improve in Quality

The Standard Malaysian Rubber (SMR) Scheme introduced in 1965 by RRIM has revolutionised the presentation, quality and marketing of NR. Under this scheme, rubber is technically graded based on technical specifications instead of the traditional visual grading system used for rubber sheets and remilled crepes. It is essentially a quality control scheme which guarantees standards and improves marketing so as to compete with the synthetic rubber industry.

New rubbers

In line with the government's policy to increase the production of value-added locally, RRIM together with TARRC in the United Kingdom, has developed new rubbers such as epoxidised natural rubber (ENR), deproteinised natural rubber (DPNR), thermoplastic natural rubber (TPNR), etc. These materials have opened up new applications especially in heavy duty engineering including earthquake isolators. Another important development is the liquid natural rubber (LNR) which has several industrial uses.

Downstream

From its early beginnings as a tree gum used as bouncing balls and waterproofing articles by the natives of South America, natural rubber has evolved into a versatile industrial raw material. Today, it is used in thousands of products ranging from simple elastic rubber band to massive earthmover tyres.

Rubber products manufacturing has been identified a priority industry in the Malaysian Industrialisation Programme. The Government, through the RRIM, has established a multi-million ringgit modern Technology Centre to help speed up its industrialisation programme. Among other things, this centre provides advice on various aspects of the manufacture of rubber products including process evaluation, product design and testing.

A selection of the manufacturing technology of rubber products which have been adopted by the rubber industry are as follows:

Engine mountings for isolation of engine vibrations from the rest of the vehicle

Cutless bearings for protection of the boat propeller shafts

Lifejackets which use a low density microcellular NR/EVA blend

NR rail pads which act as rubber cushions between the rail and concrete sleepers

Shooting range floor tiles to trap bullets

Improved tyre valves for the automobiles

Runway sealants based on NR and oil-resistant SR

Oil palm bunch waste rubberised coils

Radiator hoses based on NR and EPDM for automobiles

Thermoplastic rubber-based paints for flexible rubber toys

Rail crossing sealants based on NR and NBR

Airbrake diaphragm compounds for use in air brake systems of motor vehicles

Exhaust hangers for flexible attachment of a vehicle exhaust to chassis

Carfloor plugs for the Proton car

Other rubber automotive components developed for the vendors of Proton include weather strip, bushing, engine dipstick, side mirror housing, etc

Development of non-sulphur essentially nitrosamine- and nitrosatable-free formulations for prevulcanised latex

Development of low extractable protein latex and refinement of processing techniques like water leaching and improved chlorination to overcome or circumscribe the occassional reported occurences of Type 1 allergy attributed to the use of natural latex gloves. Associated with this effort is the development of quantitative methods (Bradford/Lowry/RRIM modified Lowry/ SE-HPLC) of determining the total water extractable protein at very low levels and immunological techniques (ELIZA/RAST) for the assay of allergenic proteins

Waste Management

The RRIM is ever conscious of its responsibility in helping the rubber industry to develop in an environment-friendly way. R & D efforts in developing the cost-effective technologies to rubber product factories are :

Anaerobic and aerobic ponding cum rubber trap systems

Aeration system for treatment of rubber effluent from factories having limited land area

Anaerobic digestion system for pre-treatment of rubber factory effluent and recovery of bio-gas as an energy source

Land application of nutrient-, element- and water-rich rubber effluent in oil plam and rubber holdings

Powdered rubber from waste coagulum generated from prevulcanised latex production

Recycling of rubber product waste in partnership with the private sector

Laboratory services

With more than half a century of research and development work,
LGM is in a position to offer unique technological back-up facilities and information
services to extend the benefits of R&D to all sectors of the industry.
RRIM maintains a number of laboratories to render both internal R&D support as well
as to assist the rubber industry to continually improve the quality and range of
technically specified rubber production and develop new rubber products.
The RRIM also serves as an independent third-party certification testing and sampling body.
Some of the RRIM laboratories are accredited to ISO/IEC Guide 17025 quality management
system under the national SAMM Laboratory Scheme of the Malaysian Accreditation Council.
RRIM is itself an accreditation body for SMR laboratories under the SMR Scheme and
the PT Coordinator under the International Rubber Association (IRA) Scheme of
Approved International Rubber Referee laboratories for Technically Specified Rubber

The MRB is also a resource centre for the supply of trained, experienced and highly qualified manpower for the rubber industry especially the downstream rubber products sector. The Board's Training Centre in Sungai Buloh has been involved in extension education since 1973. As a world leader of research and development in natural rubber, the MRB is in a position to conduct any form of training to fulfil every requirement of the NR industry. Courses offered include plantation and industrial courses as well as attachment training. In recent years, training of entrepreneurs on the manufacturing of rubber products has been incorporated into the training programme in line with the Industrial Master Plan. This is regarded as a form of transfer of technology to the industry.

Future research

Future research will be geared to meet the changing scenario of the rubber industry. Greater emphasis will be given to the downstream sector R&D in tandem with the government's policy on industrialization and value-added downstream activities. Notwithstanding this, selected areas of R&D in the upstream sector will continue to be emphasized in order to maintain the industry's competitiveness. Also, priority attention would be given to projects which will lead to 'breakthroughs' in research findings.

In addition, R&D activities of the MRB will be one that is industry-driven and relevant to industry's needs and requirements. Concomitant with this greater emphasis will be given to commercialisation of research findings.

A method of concentrating or creaming rubber latex comprises treating the latex with an organic colloid in the presence of a substance, which is neither alkaline nor acid and is more volatile than water. It has been found that the rate of creaming of latex with gum tragacanth can be greatly accelerated by treating the gum tragacanth with a small amount of certain non-acid, non-alkali, organic liquids before admixture with the latex. Acetone is a suitable substance for this purpose or an aliphatic alcohol such as methyl or ethyl alcohol. The concentrating action starts in approximately one hour as compared with four or more hours for latex treated with gum tragacanth alone. Carrying it out in a centrifuge may accelerate treatment. When the latex is dried the alcohol disappears.

Concentration of latex by creaming is effected by the addition of seed powder obtained from legumes of the tribe Amherstieae or sub-order Caesalpiniea, more especially the tamarind tree (Tamarandus indica). The seeds are roasted until the husks become brittle and easy to remove. After shelling, the seeds are ground and a solution of 3% concentration is prepared by boiling the powder obtained with the appropriate amount of water for one hour. The prepared solution is added to latex in an amount calculated to give 0.3 parts by weight of tamarind seed per 100 parts of the water phase of the latex. It has been found that there is no advantage in using larger amounts of creaming agent and that high ammonia concentrations are not necessary in order to obtain maximum creaming efficiency. After creaming for 48 hours, approximately 16.5 gallons of concentrated latex, having a dry rubber content of 58.3% and an ammonia content of 0.6% were obtained.

3. RHODES, E. and SEKARAN, K.C.

Concentration of latex.
B.P. 476, 073; appl. 1935; publ. 1.12.37.

Latex is creamed by the addition of H2O solution derivatives of a fatty alcohols containing 6-18 carbon atoms per molecule, e.g. the sodium salts of the sulphonated alcohols obtained by the hydrogenation of coconut oil or sulphonated lauryl alcohol.

Peptising agents, (i) toxic kinds such as compounds of phenylhydrazine, and (ii) non-toxic kinds, such as thio-beta-naphtol, napthyl-beta-mercaptan, xylyl mercaptan and the like, are first dispersed or dissolved in a liquid compatible with latex, and then disseminated throughout the latex. The mixture is coagulated, and the heat during drying of the coagulum yields a softened rubber. A suitable emulsion for mixing with latex may also be prepared without a paste mill or homogeniser by using an emulsifiying agent such as that sold under the Registered Trade Mark Agral W.B.S. which is soluble in thio-beta-naphthol. The cost of this emulsion can be still further reduced by dissolving the peptising agent and emulsifying agent in kerosene instead of in a more volatile solvent such as benzene. For use on rubber plantation, only the non-toxic peptising agents are claimed.

Softened rubber is produced by adding to the latex an emulsion of an organic peroxide of the general formula R1 - CO - O - O- CO- R2, where Rl and R2 are aliphatic or aromatic radicals, and then coagulating the latex and simultaneously breaking down the emulsion so that the peroxide is deposited in the coagulum. Benzoyl peroxide is a suitable substance to add to the latex, data showing the effect of the addition of various proportions of the peroxide on the plasticity of the rubber being given. The softness of the rubber is markedly dependent on the conditions of drying in the initial stages. When drying normal sheet rubber, smoke-drying produces a softer sheet than air-drying, but the reverse is the case when benzoyl peroxide is present. Data illustrating this point are given. It is therefore recommended that if it is desired to prepare smoked sheet and also to secure the utmost softening from a given amount of benzoyl peroxide, the sheets should be submitted to an initial drying period in hot air at 120°F, free from smoke, followed by the required amount of smoking.

Peptising agents which are insoluble in water, but posseses an acidic grouping capable of reacting with an alkali to form a soluble salt, are added to latex as a solution in an alkaline medium. Coagulation of the latex by addition of an acid then simultaneously precipitates the peptising agents in intimate contact with the coagulated rubber. As acidic peptising agents reference is made to compounds containing carboxy, phenolic and mercapto groups. In an example, mercaptobenzthiazole 140, dissolved in 312 cc. of 2.89 N caustic soda solution, and diluted to 7000 cc. with water was added to latex of 15.63% dry rubber content in the proportion of 170 cc. per gallon. The rubber obtained from this latex had a plasticity of 0.63 when dried in air at 140°C, and of 0.80 in a 'tunnel' smoke-house. The corresponding figures without the mercaptobenzthiazole addition were 1.52 and 1.33, respectively.

Improvements in the preparation of purified latex and the preparation of rubber therefrom.
B.P. 551, 666; appl. 26.8.41; publ. 4.3.43.

The invention relates to the treatment of latex and the preparation of a purified rubber having a reduced content of nitrogen and an improved resistance of absorption of water as compared with the normal plantation product. The invention comprehends both the method of treatment and the product obtained.

To prevent yellow colouration in the preparation of crepe rubber, even when prepared from latex from Prang Besar 186 or 25 clones, the treatment includes the addition to the latex of aryl or alkyl mercaptans, or substances releasing their active radicals, in proportions not exceeding 0.1% by weight calculated on the rubber, this being insufficient to effect appreciable softening of the rubber, but effective to bleach the resulting product. In an example, 501 of clone Prang Besar 186 latex is diluted to 20% rubber content, mixed with a solution of 50g. sodium bisulphite, and an emulsion of 5 g xylyl mercaptan of zinc betanaphtyl mercaptide, and then coagulated with 40 g of formic acid in 8.1 or water.

The process of drying NR coagulum is considerably accelerated, and if desired, higher temperatures can be employed without causing blistering, by adding to the latex prior to coagulation formaldehyde, salts of heavy metals such as lead, chromium, and zinc, and urea or vegetable or synthetic tanning agents. In comparison with a drying time of 8 days for untreated coagulum, coagulum treated with 0. 28% (on the dry rubber) of zinc sulphate dried in 5 days, with formaldehyde 0.18% in 2 days, and with formaldehyde 0.1% with zinc sulphate 0.1% in 3 days. The effect is believed to be due to a modification of the protein structure in the body of the drying rubber.

The invention relates to compositions suitable for the treatment of rubber bearing Hevea for the purpose of stimulation of yield and/or bark renewal. The invention provides improved compositions suitable for treating Hevea for the stimulation of yield and/or bark renewal and not capable for forming stable dispersions in aqueous media including a lower alkyl ester of 2,4,5-trichlorophenoxyacetic acid in which the alkyl group contains up to five carbon atoms dissolved in vegetable oil of a mixture of vegetable oil and mineral grease.

This invention relates to the stabilisation of soil for the construction of foundations for roads, footpaths, runways or the like, wherein unvulcanised rubber natural or synthetic rubber latex, with or without an appropriate binder which is not a vulcanising or a swelling agent, is mixed into the soil. Cement is also added. The advantages of using the invention are that unvulcanised rubber latex possesses marked characteristics of flexibility, pliability, tenacity, adhesion and resistance to temperature susceptibility, without the disadvantage of rigidity and liability to cracking as shown in normal soil/cement stabilised foundation or surfacing.

This invention provides a method whereby a novel type of raw natural rubber is prepared which differs from ordinary natural rubber in that it has less tendency to swell at the calender nip or extruder die even when it is uncompounded or only lightly compounded with fillers and plasticisers. It also calenders, extrudes and otherwise moulds with a remarkably smooth surface after only a short period of mastication. It provides a method of preparing raw natural rubber in crepe or sheet form by coagulating natural rubber latex which has been mixed with latex that has been subjected to vulcanising ingredients which have been removed by centrifuging.

Hevea latex concentrate containing less than 0.5% and more than 0.15% ammonia is preserved by the addition of a selenium alkyl dithiocarbamate (e.g. selenium diethyl dithiocarbamate). Between 0.01% and 0.1% of a surfactant (e.g. ammonium laurate) also may be added.

It has been found that a considerable number of bacteria survive the usual methods of preserving latex, for example by the addition of ammonia. The invention claims the use of small proportions of a sulphonamide. These compounds are stable in an alkaline medium and can be mixed to give solutions which are micro-organisms. The sulphonamide may be sprayed on the tapping cut, or added to the collecting up or to latex already containing ammonia. The concentrations should exceed 0.001%. Sulphanilamide, sulphapyridine, sulphatiazole, sulphadiazine, and sulphamerazine are amongst the suitable products listed.

This invention relates to the preparation of compositions of natural rubber with reinforcing materials. One method of incorporating such reinforcing materials into rubber is to mix a dispersion or solution of the reinforcing material with latex and to coprecipitate the mixture by addition of acid or other precipitating agent. When large quantities of reinforcing fillers are added to latex, the mixture upon acidification does not form a continuous coagulum but a flocculated precipitate which is impossible to sheet on a crepeing small mill in the normal way. This can be avoided by application of heat at controlled temperatures to the mixture and/or the acid coagulant and also during milling. Fillers, which can be incorporated in this way, are lignin, carbon black, silica, silicates, clays and synthetic resins, e.g. polystyrene.

This invention relates to the preservation of latex and latex concentrates by the addition of antibiotics. Known latex preservatives permit the survival of bacteria. Antibiotics, e.g. penicillin, streptomycin, oxytetracycline, chlortetracycline and chloramphenicol, are claimed as preservatives for natural rubber latex and these can be sprayed on the tapping panel, poured into the tapping cup, or added to the latex at the collecting station. The latex is then concentrated and a detergent, which may or may not be bactericidal, or stabilising soap is added to increase its mechanical stability.

The invention relates to the preservation of natural rubber latex, both on short or long term basis. On a short-term basis, anti-coagulants are added to the latex prior to the making of sheet and crepe, and temporary preservatives are added to it prior to the preparation of concentrate. On a long-term basis, it is for the preservation of latex concentrates during shipment and storage prior to use. The temporary preservation of fresh latex is of importance in avoiding blemishes in sheet rubber produced from the latex, particularly bubbles and dark colourations. The additives of this specification, ammonia and boric acid are superior to formaldehyde and ammonia in that a sheet of light colour is produced.

The invention relates to the preservation of natural rubber latex obtained from Hevea brasiliensis, both on a short term basis for fresh latex, including anticoagulants added to the latex prior to the making of sheet and crepe, temporary preservatives added to latex prior to the preparation of concentrates, and on a long term basis for the preservation of latex concentrates during shipment and storage prior to use. It is desirable in carrying out the preservation treatment to add the ammonia and boric acid anticoagulant (also referred to as ammonium borate) as soon as possible after tapping although appreciable improvements of the product are effected if the anticoagulant is added at any time before acid coagulation.

The strength of weak gels, such as latex coagulum, is measured by applying a small cyclic torsional stress, through the use of rotating stainless steel bob. This is done in one direction then in the reverse direction, and recording the stress required to produce the constant rnaximum strain at the end of each cycle. The strain is below the yield value of the material and applied slowly so as to discriminate between viscosity and structural effects.

Improvements in and relating to the preparation of rubber.
B.P. 869, 283; appl. 30.7.57; publ 31.5.61.

Ageing characteristics of natural or synthetic polyisoprene elastomers are improved by adding to the latex of the raw polymer reducing agents, including polyalkyline polyamines, e.g. diethylene triamine, triethylene tetra-amines or tetra-ethylene pentamine; alkali metal sulphites or bisulphites; or aromatic amines such as benzidine or phenylene diamine. A chelating agent such as ethylene diamine tetra-acetic acid or one of its salts may also be added to chelate heavy metal ions which catalyse the decomposition of rubber peroxides.

The formation of volatile fatty acids is inhibited by adding, before or immediately after concentration, an enzyme poison, especially not more than 0.2% of zinc oxide, in addition to any bactericide. Coagulation of the latex is thus avoided.

Superior processing characteristics can be imparted to a wide range of SR and NR including lower grades of NR by blending them in suitable proportions with a masterbatch. The masterbatch contains a high proportion of vulcanised rubber particles (preferably 80% or 90%) embedded in a matrix of unvulcanised latex with field latex followed by coagulation. The masterbatch will readily blend with raw rubber to give mixtures containing the required proportion of vulcanised particles, usually 20%, to produce a superior-processing product. Both wet and dry mixing processes are claimed. In an example, a rubber made by this method gave an extrusion swell of 18.7% when it was made into a tyre tread compound, compared to a value of 32.5% for the remilled crepe control.

23. WREN, W.G.

Concentrated latex. B.P. 875, 530; appl. 30.7.57; publ. 23.8.61.

Hevea latex, concentrated and preserved by the usual means is relatively unstable when first prepared but usually 'matures' during shipment, acquiring a degree of stability acceptable to the user. Latex from some of the newer clones, however, is extremely slow to mature, and moreover, has a lower degree of stability after maturation. Mild oxidation accelerates maturation but the rubber is thereby rendered softer and more susceptible to ageing. The present invention contemplates the usual maturation by mild oxidation but prevents degradation of the rubber by the addition, preferably before aeration, of polyfunctional amines as disclosed in B.P. 869, 283. These interact with peroxide groups and include such amines as benzidine, phenylene diamines, or polyalkylene polyamines such as tetraethylene pentamine; sequestrants such as ethylene diamine tetra-acetic acid also may be used.

The latex is preserved by the addition of at least 0.001% w/w of a thiobi-halophenol, particularly 2,2'-thiobis-(4, 6 dichlorophenol), added in the form of an emulsion or dispersion of (preferably) as an alkali metal or ammonium salt. The compounds have outstanding anticoagulation, and preservative activity and are free from discolouration.

25. TAYSUM, D.H.

Production of latex.
B.P. 886, 341; appl. 8.2.57; publ. 3.1.62.

Bacteria are prevented from entering latex while it is still in the tree and during emergence, with the resulting production of very white concentrated latex of very low volatile fatty acid content, of sheet rubber free from fermentation bubbles, and of very pale crepe rubber. Methods of protection against infection include application of alkaline detergent bactericidal and/or bacteriostatic dressings to the tree around the region of tapping, in conjunction with antibiotic injection. Also removal of a section slightly deeper than usual (1/5 in. instead of 1/20 to 1/30 in.) will remove all previously contaminated latex vessels and the subsequent maintenance of aseptic conditions will prevent reinfection.

A liquid bactericidal dressing of a given composition is painted round the tapping cut on the tree and is effective for several months in giving increased yields of improved quality latex, e.g. very white concentrated latex of low initial volatile fatty acid content. This gives sheet rubber tree from fermentation bubbles or very pale crepe rubber. The method is slightly less effective than the antibiotic injection method claimed in B. P. 886, 341 but can be easily carried out by unskilled workers.

Improved durability and crystallisation resistance are obtained by treating rubber with a thiol compound. It is now found that natural latex contains an inhibitor which is removed by adding formaldehyde and allowing to stand 24 hours and preferably 48 hours before reacting with the thiol. Intermediate stages of dilution and stabilisation may be included in the process.

Small quantities of ethylene oxide (of the order of 0.1% to 1 %) can be used to preserve field latex and latex concentrates for periods of several days. The preservative causes no pH changes in the latices, is suitable for use with latices used to make pale sheet and crepe rubber, and requires no modification of normal manufacturing processes.

This invention is for improvements in or relating to the stabilisation of natural rubber and is concerned with the treatment of rubber latex to produce a rubber which has improved storage properties. Research has indicated that the hardening of unvulcanised NR during storage results from crosslinking via oxygenated functional groups, such as carbonyl or carboxyl. By adding a reactive derivative of ammonia, of the general formula XNH2, where X is a hydroxy or hydroxyalkyl group, or aromatic nucleus free from any basic group or basic substituent. The above mentioned ammonia derivative added to the latex is preferably between 0.1% and 5% by weight of the rubber solids in the latex. In examples, hydroxylamine, naphthylamine, and ethanolamine were used.

A dry rubber having superior processing properties is made by blending a casein-rubber masterbatch, comprising a NR or SR having casein dispersed therein in an amount of between 20% and 80% by weight of the resultant rnasterbatch, into a dry NR or SR in an amount such as to provide a blend containing 10% to 20% of casein by weight of the final blend. SBR or neoprene may be used. The improvement includes a reduction in extrusion swell an increase in extrusion rate.

A masterbatch is made by admixing an aqeous solution of polyvinyl alcohol with a rubber latex co-precipitating the two by coagulating the latex. Also claimed is a method of producing a dry rubber blend having superior processing properties by blending the masterbatch into a dry NR or SR in an amount such as to provide a blend containing 10% to 20% of polyvinyl alcohol by weight of the final blend. A reduction in extrusion swell and an increase in extrusion rate is achieved by using the resulting blend.

A process for the preservation of field latex (or a concentrate) by adding to it 0.05% to 0.002% of 8-hydroxyquinoline, 0.1% to 0.3% of ammonia, and 0.5% to 0.1% of boric acid and/or 0.1% to 0.01% of zinc oxide, by weight of the latex is claimed. This invention is particularly applicable to the treatment of concentrated latex which may be produced by centrifuging with or without chemical creaming.

This invention relates to the production of modified rubbers of the kind known as graft polymers. It comprises successively polymerising a plurality of separately added increments of a vinyl or vinylidene monomer or monomers in a natural or synthetic rubber, using an organic peroxide or hydroperoxide as the polymerisation initiator. The vinyl or vinylidene monomer or monomers being polymerisable in the presence of the latex and each of the increment is being substantially completely polymerised before the next increment is added. The use of methyl methacrylate as the vinyl monomer is described in the examples.

This invention includes a process for the production of an oil/rubber masterbatch which comprises emulsifying a rubber extender oil in a latex of vulcanised natural or synthetic rubber having a combined sulphur content of 1% to 2.5% by weight of the latex solids, co-precipitating the latex and emulsified oil in the form of a crumb and separating the crumb from the aqueous reside. The precipitated crumb is usually washed and dried. Because of the vulcanised particulate structure of the latex, the oil extended crumb presents no difficulty in drying. The co-precipitation of the latex and emulsified oils is usually effected by coagulation of the mixed emulsion, by the addition of an acid, such as formic acid.

This invention is for improvements in or relating to the reinforcement of rubber and is directed to the reinforcement of natural and synthetic rubbers in latex form. It comprises reacting hydrazine with formaldehyde in situ in the latex. The process of the invention results in the production of a hydrazine formaldehyde resin intimately associated with the dispersed polymers of the latex. The resin effects a reinforcement of the latex which makes it possible to produce foam rubbers of enhanced compression modulus and films of increased modulus and strength from Hevea latex concentrate. The effect obtainable with latices made from synthetic elastomers is less marked than with natural rubber latex which may be treated in its various conventional forms, e.g. field latex, concentrated latex and latices containing preservatives such as ammonia.

The present invention provides a method of preserving the latex until it is made into crepe or sheets and to effect a stabilisation of the hardness of the resulting rubber. Such rubbers, apart from being free of blemishes and bubbles, have the advantage that they do not undergo significant changes in hardness on storage and is based upon the discovery that hydrazine is an effective preservative and crosslinking agent for rubber. The addition of hydrazine to latex for the purpose of preserving it, or as an anticoagulant, can be conveniently made to field latex either in the cup in which it is collected in or to the field latex in the collecting vessels or bulking tanks.

A process for the reinforcement of natural and synthetic rubber latices comprises reacting hydrazine with formaldehyde in situ in the latex. Also claims articles formed by foaming such a resin-containing rubber latex, and articles formed by dipping a form into resin containing rubber latex. The application of this process to natural rubber and styrene/ butadiene copolymer is described.

A method of preventing and/or reducing bacterial infection in the tapping of a rubber tree and in the latex by forming an air-tight enclosed space surrounding the tapping panel on the tree. This is done by sealing a gas-impermeable sheet of material, e.g. polyethylene, around that part of the trunk containing the tapping panel, to leave an enclosed air space sealed from the atmosphere, creating a non-coagulating bactericidal atmosphere within the enclosed space prior to the tapping operation, tapping the tree, and collecting the latex between the enclosed space. The bactericidal atmosphere is preferably created at least 12 hours before tapping and can be produced by the introduction of ammonia or formaldehyde into the enclosed air space.

A stabilised natural rubber latex concentrate which may be produced by centrifuging, creaming or evaporation, which concentrate contains from 0.2% to 0.8% by weight of ammonia, from 0.02% to 0.2% by weight of a fatty acid soap and from 0.1% to 2.0% by weight of an inorganic sodium or potassium salt and/or from 0.02% to 0.3% by weight of a mono-or chlorophenol or of a nuclear alkyl substitution derivative. The said chlorophenols may be used as such or in the form of the sodium, potassium or ammonium salts.

Synthetic rubber is given improved processing properties by mixing synthetic rubber latex which has been vulcanised to a sulphur content of 1% to 2.5% by weight of the latex solids, with an unvulcanised, sulphur-vulcanisable synthetic and/or natural rubber latex to give a latex mixture containing 15% to 20% by weight of vulcanised rubber based on the solids content. It is then coagulated, preferably with formic acid. The vulcanised synthetic rubber latex may in part be replaced by a vulcanised natural rubber latex. When the mixture of latices contains more than 50% of the vulcanised component it is suitable for use as a masterbatch.

Rubber in crumbled form is obtained by milling a masterbatch comprising a wet coagulum of natural or synthetic rubber latex having compatible oil dispersed with wet NR in the form of a coagulum or solid mass. The masterbatch is suitably prepared by emulsifying or dispersing the oil in the latex and coagulating the resultant mix. The latex is suitably vulcanised latex or a mixture of vulcanised and unvulcanised latices. Tbe masterbatch may contain up to 90 wt. % of the oil. The amount of the masterbatch used is preferably such that the crumbled rubber contains 3 to 10 wt. % of the oil.

Rubber in crumbled form is produced by milling an incompatible oil and wet natural rubber in the form of a latex coagulating or solid mass. The crumbled rubber does not knit back to a crepe even on repeated milling or on standing. The mixture of the oil and rubber is suitably obtained by mixing the oil in the form of an aqueous emulsion or dispersion with natural rubber latex and then coagulating the mixture. The oil is suitably castor oil or silicone grease and is incorporated into the rubber in an amount of 0.25% to 2% by weight of the rubber.

Ammonia-preserved NR latices (including concentrates) and synthetic cis-polyisoprene latices are stabilised against free-thaw coagulation by the addition of a small amount of a salt of salicylic acid. Suitable salts are the sodium, potassium, ammonium and triethanolamine salts. The latices may also contain secondary preservatives and surface active agents.

A method of improving the raw ageing characteristics of lower grade rubbers and skim rubbers by coagulating it with an aqueous solution of oxalic acid is described. The oxalic acid is employed in an amount from 0.01% to 1.0% of the solid oxalic acid based on dry rubber content by weight of the rubber undergoing treatment. The rubbers may be in finely divided form, i.e. in the form of latex or in dry comminuted form.

45. SHIPLEY, F.W.

Improvements in or relating to the production of rubber compositions.
B.P. 1, 125, 801; appl. 5.2.65; publ. 5.9.65.

A NR/carbon black masterbatch is produced directly from a natural rubber field latex. An aqueous dispersion of carbon black stabilised with a dispersing agent is added to the latex, optionally preserved with up to 0.2 wt. % ammonia. The mixture is agitated to effect uniform mixing and is further agitated until the rubber flocculates and finally coagulates. The coagulum is then separated from the serum. The carbon black may be used in amounts of up to 100 wt.% of the rubber in the latex. If desired, an aqueous emulsion of mineral oil is intimately mixed with the latex prior to the addition of the black.

The present invention relates to a process for the coagulation of natural rubber latex, which comprises adding to fresh rubber latex an amount of phosphoric acid sufficient to reduce the pH of the latex at least to the coagulation point. The latex may contain an amount of ammonia sufficient to preserve it from substantial biological spoilage. The amounts of phosphoric acid added are to produce a pH value in the range of 6 to 3 in the latex depending on the vulcanising characteristics required of the rubber in accordance with existing practice. The use of phosphoric acid in place of formic or acetic acid results in dramatic reduction in the iron pick-up from the creping rollers by approximately an order in magnitude with a consequent improvement in the colour of the sheet rubber. The reduction of iron contamination in the latex is accompanied by a dramatic reduction in the corrosive rusting of the creping rollers.

This invention provides a method of coagulating Hevea latex as obtained from the tree or in a diluted form. It comprises mixing with the latex at a pH not above 8; (I) an anionic surfactant whose anion has the general formula:

CH2 - COOR
|
CH2 - COOR
|
SO3

CH2 - COOR | CH2 - COOR | SO3

where R is an alkyl group, and (II) a salt of an alkaline earth metal (calcium, strontium or barium). R in the first additive is preferably an alkyl group of the type CnH(2n+1) and particularly where the alkyl groups is a branched chain and n is from 4-9, the coagulating efficiency then increasing with chain length. Particularly preferred additives are dioctyl sodium sulphosuccinate or dinonyl sodium sulphosuccinate. In general, the solvent used affects coagulating efficiency.

This invention describes a simple and economic method of precipitating rubber from latex by an alternative path that does not involve the precipitation of serum protein at the same time. It provides a method of coagulating

CH2 - COOR
|
CH2 - COOR
|
SO3

Hevea latex, which comprises adding an anionic surfactant having an anion of the general formula :

CH2 - COOR | CH2 - COOR | SO3

where R is a saturated alkyl group, in an amount to coagulate the latex. A dialkyl sulphosuccinate is used as surfactant.

A method of extending a natural rubber with oil is described. The method comprises by comminuting and drying a natural coagulum and bringing the formed loose aggregate of rubber particles into intimate contact with the compatible oil. The proportion of oil and the period of contact being such as to bring about the desired degree of extension. After extension, the rubber may be pressed to a solid block for transportation. The method was carried out at a temperature of from 50°C to 100°C.

51. SOUTHORN, W.A.

Method and apparatus for applying a gas or vapour to a tree.
B.P. 1, 192, 528; appl 14.11.68; publ. 20.5.70.

A flexible frame, e.g. of expanded polystyrene, is stuck to the trunk of the tree, e.g. by natural rubber latex and a container for holding gas or vapour-generating substance(s) is secured to the container in such a way that its interior is in communication with the trunk. The gas generating substances may be chloroform, or calcium a carbide which generates acetylene by reaction with moisture from the tree. The application of e.g. acetylene, chloroform or ethylene oxide to the bark of
Hevea brasiliensis trees results in substantial increase in the yield of latex.

A method of treating rubber-bearing Hevea brasiliensis for the purpose of stimulation of yield by applying a halogenoparaffin, other than chloroform. The halogenoparaffin is a liquid and is applied in admixture with grease as a carrier to the bark below the tapping cut. The halogenoparaffin is l-bromopentane or l-bromododecane and the grease is palm oil.

This invention provides a method of preparing a vulcanisable dry rubber composition from rubber latex. It comprises dispersing in the latex the desired vulcanising ingredients in proportions to vulcanise the rubber in the latex to the desired extent, coagulating the latex in the mixture thus produced, washing the coagulum, drying the washed coagulum and homogenising the dried coagulum again under conditions such that curing does not take place. The resulting vulcanisable dry rubber composition can be processed and cured by means of conventional dry rubber processing methods and equipment. It can be moulded to give shaped articles and may be used as springs and in other engineering applications.

This invention relates to a method of extracting rubber latex from rubber bearing Hevea brasiliensis in which low intensity tapping systems are used in conjunction with chemical treatments to enhance latex flow. The chemical treatment is by the application on n-butyl ester 2,4, 5-trichlorophenoxy acetic acid.

This invention relates to the treatment of rubber-bearing Hevea brasiliensis. It provides a method of treating rubber-bearing Hevea brasiliensis for the purpose of stimulation of yield of rubber latex. The method includes applying a substance, other than a substance in the given list, which causes ethylene to be provided in or in close proximity to the latex-bearing tissues of the tree.

The invention provides a method of preserving field latex of Hevea, either diluted or undiluted, from coagulation. The method involves maintaining the pH of the latex at a value of at least one addition of urea or by making at least one addition of a nitrogenous base and at least one addition of urea. The nitrogenous base may be ammonia or an organic amine. Therefore, the pH of the field latex may be raised from its natural level (about 6.5) to 9.0 by the addition of a solution of ammonia and continuously maintained at this level by further additions of ammonia as required. It is found that after a few days a stage is reached when no further additions are required. The latex can be kept fluid indefinitely, with no further additions or only minor and infrequent further additions of ammonia.

This invention relates to the treatment of rubber-bearing Hevea brasiliensis for the purpose of stimulation of yield by the agency of ethylene. The method comprises generating the ethylene in situ by chemical reaction between at least two reactants. Preferably the ethylene is generated in situ between an ethylene-l, 2- dihalide, particularly ethylene-1, 2-dibromide, and metallic zinc, e.g., in granulated form, or an alkali metal iodide, e.g. sodium iodide preferably in the presence of an alcohol, e.g. ethanol. By the use of this reaction, a controlled and sustained supply of ethylene can be achieved over a period of weeks without the use of expensive chemicals. Five examples illustrating the invention are also included.

A process for improving the resistance to degradation of natural rubber or of a synthetic rubber having an unsaturated carbon chain is claimed. The dry rubber was reacted with a nitrosophenol or an ether or a nitrosoaniline so as to form rubber-bound groups having antioxidant properties. The reaction is performed in the presence of a salt of a thiol, which improves the resistance to oxidative degradation conferred by the rubber-bound antioxidant.

The present invention provides a method by which natural rubber latex concentrate can be chemically treated to produce latex suitable for foam manufacture but having reduced volume shrinkage in the final article resembling more closely synthetic latex. This enables a manufacturer to increase the proportion of natural rubber latex in the blend of latices used, or possibly to replace synthetic latex by natural rubber latex without altering his mould or product size.

The invention provides a process for treating rubber latex to increase the modulus of a vulcanisate. The process comprises forming a mixture of a natural rubber latex concentrate or of a mixture of a natural rubber latex concentrate and a synthetic rubber latex, with from 0. 5% to 4% by weight on the dry rubber content of the latex concentrate or mixture of a sodium, potassium or ammonia salt of a saturated fatty acid containing from 14 to 20 carbon atoms per molecule. The latex is foamed in the presence of a foaming agent other than saturated fatty acid soap, forming a vulcanised foam rubber.

The present invention provides a method of effecting adhesion between a natural or synthetic rubber and another material which method comprises heating a mixture of the rubber with, (a) an aromatic nitroso compound having the formula X-Ar-NO where X is a hydroxyl or a primary or secondary amine group and Ar is an aromatic group and (b) a polyfunctional linking agent, under pressure in contact with the material to which it is to be adhered. This is to react the rubber with the aromatic nitroso compound, and also pendent amino or hydroxyl groups in the resulting product with the polyfunctional linking agent so as to crosslink the rubber and the said other material. An advantage of this invention is that chemicals added to the rubber have the twin effects of vulcanising the rubber and of effecting bonding of the rubber to other materials.

This invention provides a method of treating natural rubber to stabilise it against undesired hardening on storage. It comprises adding to natural rubber in the solid state, hydroxylamine or an acid addition salt. Offering the following advantages, it is possible (a) to produce viscosity stabilised rubber from solid natural rubber of any origin (b) to produce viscosity stabilised rubber with a more efficient use of additive since none of the water-soluble chemical agent is lost during processing (c) to produce viscosity stabilised rubber at any desired viscosity. The application of this viscosity stabilising principle to dry compounding such as in retread compound production is desirable as the final compound maintains its viscosity on storage.

64. SMITH, J. F.

Treatment of rubber.
B.P. 1, 366, 934; appl. 10.8.71; publ. 18.9.74.

This invention relates to natural rubber, both vulcanised and unvulcanised and to a method of removing proteins from natural rubber. The method comprises incubating natural rubber latex with a proteolytic enzyme at a pH suitable for the enzyme in the presence of a soap to prevent premature thickening of coagulation of the latex and subsequently separating proteinaceous material from rubber. The acid constituent of the soap is one of the carboxylic acids from rubber soluble zinc salts.

The present invention relates to the preservation of natural rubber latex in the form of re-dispersible solids or low moisture content pastes. It comprises providing a whole natural rubber latex in admixture with dispersing agent combination which includes at least one compound selected from at least two of the groups: (a) glycosides and urea, (b) mono- and di-saccharides, and (c) alkali metal and ammonium salts of organic acids having a C7 and C30 aliphatic carbon chain, and removing water from the latex. The invention is applicable to whole natural rubber latex irrespective of the solids content. The method is applicable to fresh field, diluted field, concentrated and preserved concentrated latices.

This invention provides a method of making a solid or pasty synthetic rubber which is dispersible in water, which method comprises providing a latex of the synthetic rubber in admixture with an effective amount of re-dispersing agent, and removing sufficient water from the latex to give the solid or pasty rubber. The invention also includes synthetic rubber in solid or paste form, which contains a re-dispersing agent and is dispersible in water. It is particularly applicable to styrene-butadiene-rubber (SBR) and polyisoprene rubber.

68. JOHN, C.K.

Treatment of latex.
B.P. 1, 431, 176; appl. 5.7.72; publ. 7.4.76.

The present invention provides a method of treating latex to suppress bacterial acid production. The method comprises maintaining ammoniated whole field latex of Hevea brasiliensis at a temperature of from 40°C-60°C for a period of at least 24 hours. The ammonia is preferably present at a concentration of at least 0.2%, and preferably about 0.3%. The latex is preferably maintained at the minimum temperature at which control of VFA is achieved, which was found to be about 45°C. The use of temperatures above 60oC, adversely affects the latex properties and is expensive on fuel.

The storage hardening of natural rubber is reduced or eliminated by treatment of fresh natural rubber with an acid hydrozide containing the group -CO-NH NH2. The preferred range of addition is 0.1 to 1.0 p.p.h.r. A suitable hydrazide is naptenic acid hydrazide.

This invention provides a method of producing raw solid natural rubber bulk form. The method comprises passing a continuous stream of fresh or preserved natural rubber field latex through a heat exchanger in which the heating medium is maintained at a temperature from 100°C to 300°C so as to raise the temperature of the latex from 60°C to 110°C . Gelation of the rubber is caused to take place rapidly; optionally crumbling and drying the coagulum; and then pressing and palleting it to form raw solid natural rubber in bulk.

Rubber-bound antioxidants are produced in latex by reacting it with nitroso compounds in the presence of a metal dialkyl dithiocarbamate and a hydroxylamine salt. The reaction is carried out at 50-70°C. The process gives latices which do not discolour on standing. The ageing resistance of vulcanisates prepared from them is equivalent to that obtained by the addition of 1 p.p.h.r. of conventional antioxidant.

72. ONG, C.O.

Treatment of rubber.
B.P. 1, 484, 252; appl. 22.10.73; publ. 1.9.77.

This invention provides a method to provide viscosity stabilisation by adding to fresh solid natural rubber with an aqueous solution of semicarbazide or an acid addition salt. The amount of semicarbazide or acid solution salt added to the rubber is from 0.02% to 0.05% by weight based on the weight of the rubber.

This invention provides a composition for the treatment of living plants. It comprises a volatile or gaseous plant growth regulant releasably adsorbed on the surface of a particulate solid adsorbent together with an oliphatic or aromatic carboxylic acid or anhydride and/or dimethylsulphoxide and/or glycerol as an agent, to assist assimilation of the plant growth regulant by the plant.

The invention provides a method of preparing a preserved natural rubber latex concentrate which method comprises (a) field latex preserved from coagulation from 0.05% to 0.4% by weight of alkali, preferably ammonia, and a secondary preservative, which is a combination of an organic disulphide with zinc oxide or a bactericide (b) concentrating the field latex and (c) preserving the resulting latex concentrate by incorporating a further amount of a secondary preservative and optionally by incorporating further alkali to maintain the alkali concentration within the range 0.05% to 1.0% by weight.

This invention relates to the stimulation of yield of rubber latex from Hevea brasiliensis through the application of formulations that contain ethylene or ethylene releasing compounds. This invention is based on the discovery that palm kernel oil and coconut oil can be very effective carriers. Accordingly the invention provides a composition for stimulating the yield of rubber latex from Hevea brasiliensis comprising a yield stimulant of the kind which releases ethylene in contact with the plant tissues in a carrier comprising palm kernel and/or coconut oil.

This invention relates to compositions that will prolong the period of effectiveness of fungicides used for controlling stem diseases of Hevea brasiliensis, in particular diseases on the tapping panel. The invention provides an oil in water emulsion containing a vegetable oil, a hydropholic colloid, and fungicide selected from phenyl mercury acetate, cycloheximide and captafol for application to Hevea brasiliensis.

The present invention relates to the treatment of soil to improve the soil structure and in particular to techniques involving application of aqueous compositions containing rubber and oil to soil. It is primarily directed to two applications. Firstly, to control erosion of exposed soil, especially by heavy rainfall and on sloping terrain e.g. road cuttings and agricultural land, thereby reducing silting of natural waterways, loss of fertility and damage to installations. Secondly, it aims to improve the physical condition of soils, particularly sandy soils leading to better crop growth. This invention provides a method of improving the properties of soil by applying to it, 10³ to 105 litres per hectare of a mixed aqueous emulsion of rubber latex and an oil, containing from 0.05% to 30% by weight rubber (dry basis), from 0.5% to 30% by weight of oil and from 1% to 50% by weight on the weight of the oil of an emulsifier. Examples relating to the aspects of prevention of soil erosion and improvement of the physical conditions of soil are illustrated.

This invention relates to chemical compounds and to their use in rubber which is reinforced with silica. The main utility of the azosilane compounds of the present invention is envisaged as treating agents to improve the compatibility of silica, silicates and clays when compounded in rubber.

This invention relates to fungicidal compositions and in particular to a method of controlling Secondary Leaf Fall (SLF) in particular Oidium SLF of mature rubber using such fungicides. The fungicidal composition comprises of an emulsion or dispersion of a systemic fungicide in a light hydrocarbon oil which is non-phytotoxic to young rubber leaves. In order to enhance the stability and dispersibility of the emulsion, the composition preferably includes a surface-active agent. The fungicide is primarily intended for spraying or fogging onto rubber trees so as to inhibit the organisms causing SLF.

This invention relates to a method of maintaining the colloidal stability of natural field latex, obtained from Hevea brasiliensis, by the use of substances that are not bactericides or enzyme poisons. This permits the growth of micro-organisms in the latex system with the result that certain properties of the derived rubber are changed beneficially. Such stabilised latex is particularly suited for subsequent gelation by physical agents, such as heat or mechanical energy, prior to processing into dry rubber. Fresh field latex is stabilised against coagulation by adding to it an effective amount of anionic surfactant which has a hydrophilic-lipophilic balance value of at least 12 either alone or in combination with small quantities of ammonia and seeding the fresh latex with a portion of mature preserved latex. The amount of surfactant will be from 0.1% to 3% by weight on the dry rubber content (drc) of the latex. Where ammonia is used in combination with a surfactant, the amount used will be typically up to 0.15% by weight on the weight of the latex and amount of surfactant from 0.1% to 1% by weight on drc. Use of less than 0.1% surfactant does not generally give sufficient stabilisation to be of practical value, and use of more than 3% or 1% respectively, for ammonia-free and low-ammonia systems provides no further stabilisation and is uneconomical.

This invention relates to an instrument for extracting latex from Hevea brasiliensis and other rubber latex bearing species. An incision technique known as micro- or puncture-tapping has been experimented with and has been shown, with chemical stimulation, to give yields comparable with conventional excision tapping. Puncture tapping entails puncturing a series of holes, typically using a ca.1.0 mm diameter needle, along a vertical strip or groove of scraped bark 80 cm-100 cm long. To maintain the required level of latex yield, a latex stimulant is usually applied to the scraped bark. This puncture method of tapping can be performed very rapidly and requires little skill. The instrument used to effect tapping comprises a bradawl-like tool, having a short removable needle attached to a handle. This tool, although convenient, has numerous shortcomings. In order to use the tool, the needle is pushed into the tree and then retracted; this operation repeated many times over during tapping of a large number of trees. The double operation requires considerable effort and thus muscle fatigue sets in, typically after about one thousand punctures have been made. The present invention seeks to improve on the existing tools used for rubber tapping, particularly incision tapping.

This invention relates to the use of natural rubber (NR) in the manufacture of coated agricultural materials. In particular it relates to the manufacture of slow release fertilisers by coating fertiliser materials with a coating of NR derived from modified NR latex.

The present invention relates to the processing of Hevea latex into dry rubber. It provides a method of producing solid coagulated natural rubber which comprises (a) ammoniating field latex, preferably freshly tapped filed latex, to a pH of at least 9.0 and preferably 9.5 (b) stabilising the ammoniated latex an a nonionic surface active agent (c) fermenting the ammoniated latex for a period of at least 3 days under anaerobic conditions (d) treating the ammoniated, stabilised latex, before or during fermentation with at least one proteolytic enzyme (e) during the fermentation and enzymatic treatment maintaining the pH of the latex at least 9.0 and preferably at about 9.5 (f) optionally diluting the fermented and enzymatically treated latex with water and (g) coagulating the latex with acid.

An agricultural material composition comprises particles of an agricultural material, e.g. a fertiliser, coated with a layer of protein degraded pre-vulcanised natural rubber to provide slow-release properties. The particles preferably have a diameter of from 0.5 mm to 12 mm, and the thickness of the rubber layer is preferably from 10 microns to 250 microns.

This invention relates to the use of natural rubber (NR) field latex for the production of epoxidised natural rubber (ENR). In particular it relates to a method of treatment of NR field latex so that ENR can be prepared from it.

The present invention provides a method for reducing the molecular weight of rubber in latex which has a number of advantages, in particular, the range of temperature over which the reaction may be performed, the wide range in extent of reduction in molecular weight which can be achieved and the relative ease of control over the extent of reduction. The process comprises adjusting the pH of the latex to an appropriate value in the presence of a suitable surfactant, where necessary, and treating the latex under specified conditions with a combination of an oxidising agent and a reducing agent, that is, a redox system. Preferred oxidising agents are peroxidic compounds, which may be hydrogen peroxide, or its organic derivatives such as alkyl, cycloalkyl and aralkyl hydroperoxides, or inorganic peroxy compounds such as perborates, percarbonates, perchlorates and persulphates. Preferred reducing agents are alkali and alkaline earth metal nitrites, ammonium nitrate, alkyl nitrites such as amyl nitrite, and sodium and potassium chlorite.

A method for reducing the molecular weight of rubber in latex form or in wet coagulum form comprises treating the latex with an oxidizing agent and a reducing agent. The oxidizing agent is air, oxygen or peroxide and the reducing agent is a metal nitrite and/or a metal chlorite. The method is particularly suited for use with natural rubber latex, including epoxidised natural rubber latex. Depending upon the degree of reduction of the molecular weight, the method may be used (i) in the preparation of liquid rubber, (ii) in the preparation of improved latex adhesives and (iii) in the control of the viscosity of rubber during normal production.

A method for the treatment of natural rubber field latex.
MY-101622-A; appl. 19.9.87; publ. 17.12.91.

A method for the preparation of epoxidised natural rubber (ENR) from fresh natural rubber field latex is described. This comprises (i) incubating the field latex with a proteolytic enzyme at a pH suitable for the enzyme, (ii) epoxidising the enzyme-treated field latex to the desired mole % level of epoxidation, (iii) coagulating the epoxidised natural rubber latex, and (iv) crepeing, washing, crumbling and drying the epoxidised natural rubber. The amount of enzyme present and the incubation conditions are such that the enzyme-treated field latex, when subsequently processed into ENR latex, has improved coagulation and crepeing properties.

A continuous method for coagulating natural rubber latex comprises passing a stream of latex through a vertical column. The latex travels down the column as a thin film on the inner surfaces thereof until it comes into contact with steam that has been injected into the column. The latex is rapidly heated by the steam and coagulates, the resulting coagulum being collected at the bottom of the column. The method is particularly suitable for the coagulation of epoxidised natural rubber latex. Apparatus for performing this method is also described.

This invention relates to novel adhesive compositions derived from epoxidised cis-1,4 polyisoprene. In particular, it relates to the adhesive compositions based on epoxidised natural rubber (ENR) for bonding rubbers to a variety of substrates including metals and rubbers. The adhesive composition comprises epoxidised natural rubber with an epoxide content in the range of from 1 to 90 mole % and optionally, a filler in an amount of up to 100 parts by weight per 100 parts by weight of the epoxidised natural rubber and also at least one of the following: a carboxylic acid, a chlorinated polymer, and a phenolic resin.

Serum concentrates are disclosed which consisting essentially of specified contents of a non-rubber component remaining in aqueous solutions resulting from coagulation of and separation of all rubber hydrocarbons from natural rubber latices. The non-rubber component includes proteins, saccharides and other important materials. The concentrate product is applied particularly to fertilisers, rubber additives and bacterial culture media.

92. KAIDA BIN KHALID (RRIM and UNIVERSITI PERTANIAN MALAYSIA)

Apparatus and method for the determination of the dry rubber content of rubber latex.
MY-106441-A; appl. 17.8.90; publ. 30.5.95.

Apparatus for the determination of the dry rubber content of rubber latex, by the detection of reflected microwave signals, includes a meter component (1) and a sensor component (2). The sensor comprises a microwave oscillator (18), a transmitter (5), a receiver (6) and a microwave detector (19). During operation, the sensor is immersed to a predetermined depth in-the sample of rubber latex under analysis. In an alternative embodiment, the sample of rubber latex is held within a container, either fixed or removable, positioned adjacent to the sensor. The apparatus is capable of giving accurate and rapid results, and is sufficiently portable and simple to operate to be suitable for use in the field. A method for determining dry rubber content, involving the use of the aforementioned apparatus, is also described.

93. LOO, C.T.

Adhesive compositions.
MY-106610-A; appl. 21.7.89; publ. 30.6.95.

Adhesive composition based on epoxidised natural rubber may be used as cover adhesives to bond a variety of vulcanisable and vulcanised rubbers to metals or to themselves. These adhesive compositions comprise epoxidised natural rubber with an expoxide content of from 1 to 90 mole%, preferably about 50 mole% and optionally a filler and/or a curing agent. In addition, the compositions also comprising at least one of a carboxylic acid, a chlorinated polymer and a phenolic resin have use as general purpose primer adhesives for metals and as single coat adhesives for bonding unprimed metals and chlorinated polymers. The adhesive compositions additionally containing from 10 to 60% by weight of sulphur have use in bonding polar and non-polar robber to primed or unprimed metals and to themselves.

Purified L-quebrachitol can be recovered in increased quantities from serums byproduced upon treatment of rubber latices. Concentrated solutions or pulverised solids of serums are dissolved in selected grades of methyl alcohol and under specified extraction conditions.

Method and apparatus for the pyrolysis of wood with by-product recovery.
MY-107320-A; appl. 18.6.90; publ. 30.11.95.

A semi-continuous method and apparatus for pyrolysis of wood such as rubber wood into charcoal and other by-products, comprising a step of heating wood placed inside an inner retort (10) within an outer retort (20) and a step of partially condensing the issuing vapour. As a result, charcoal is obtained in the retort (20), tar in a tar separator (40), and pyroligneous acid and other gas fractions in a receiver (60). This process is clearly illustrated in
Figure 1.

A method of producing a genetically transformed fluid-producing plant comprises: i) inserting into the plant tissue a gene or gene fragment controlling the expression of a target product, and ii) regenerating a plant from said tissue, the genetically transformed plant being capable of expressing the target product in the fluid that it produces. There are also provided clones of genetically transformed fluid-producing plants which contain in their cells a chromosomal insert such that the target product is expressed in the fluids that the plants produce. There is further described a method of producing a protein or other target product which comprises: i) harvesting the fluid from a genetically transformed fluid-producing tree or plant, or a clone thereof, and ii) recovering the target protein or other product from said fluid. Most preferably, the plants are rubber (Hevea) plants and the genes are foreign genes that code for pharmaceutically valuable protein products which can be harvested in the latex produced by the plants.

Apparatus for effecting gas-liquid contact comprising a vertical column (1) through which the gas and the liquid are passed countercurrent to one another. The column has an axially located rotatable shaft (2) upon which is mounted on or more discs (3), which may have vanes (7). The column also includes a feed distribution tray (4) and at least one liquid redistribution tray (5), either or both of which trays may contain tubes (11) permitting the passage of gas, located at intervals along its length. The apparatus is intended for use in transferring gas dissolved in a liquid flowing downwards through the column, or for transferring a soluble component in a gas-phase mixture into a liquid absorbent. It is particularly suited for use in the removal of ammonia from skim latex during rubber processing
operations.

A device for tapping a latex-bearing tree includes a frame (11, 12) for attachment to the tree, and an operating mechanism which is carried by the frame (11, 12) and comprises a punch (26) and means (16) to drive the punch (26) into the bark of the tree and then to withdraw the punch (26). After each such operation the operating mechanism (16) is moved (30, 32) a step virtually relative to the frame by a motor (18). The motor (18) serves also to actuate the operating mechanism. The most illustrative drawing is Figure 1.

Improvements in the method of stimulation and tapping of Hevea brasiliensis.MY-111156-A; appl. 1.3.91; publ. 20.9.99.

There is disclosed improvements in the method of stimulation and
tapping of Hevea brasiliensis, which improvements comprise of treating
Hevea trees with gaseous ethylene for stimulation of latex flow and
tapping such treated trees with tapping systems comprising of punctures for
increased latex flow and higher yield productivity. An applicator is fixed
over a previously bored hole on the tapping panel and the ethylene gas is
fed through a tube fitted into the bored hole through an aperture on the body
of the applicator. The bored hole and applicator are positioned on the bark of
the tapping panel at the desired location on the trunk of the rubber tree.

The present invention relates to cDNA encoding small rubber particle-associated protein (SRPP) which binds to small rubber particle derived from the latex of H. brasiliensis, recombinant SRPP deduced from the cDNA, recombinant microorganisms transformed with the recombinant expression vectors and method for synthesis of rubber using the recombinant SRPP. The recombinant SRPP expressed in the recombinant microorganisms can be applied for the rubber synthesis in the presence of rubber particle.

Apparatus for extracting latex from rubber latex bearing species comprising a housing with a moveable rod wherein a puncture is made in the tree bark using the rod and latex flows through the housing passage and a tubing into a closed container with an air filter. One end of the housing is in the form of a cup of attachment to tree bark. The housing also contains a valve for sealing the housing passage after puncturing. The apparatus is intended for extracting natural rubber field latex that can be processed to give a high quality rubber due to the absence of chemical preservatives and minimal amount of acid used for late coagulation. In addition, the liquid-phase containing the non-rubber components can be obtained in the original form without toxic chemical additives. This permits the production of non-toxic liquid from field latex that contains valuable biochemical for further exploitation.

A process of treating latex is described in which a fatty acid soap and a non-ionic surfactant are added to the latex in proportions such that the colloidal stability of the treated latex is such the latex is suitable for dipping processes. In an example the fatty acid soap is potassium laurate and the non-ionic surfactant is alkyl phenol ethoxylate.

Remarks:
This application was filed on 17.04.2003 as a divisional application to the application mentioned under INID code 62.

This invention relates to allergenic proteins of natural rubber latex in substantially purified form, their production and their use, together with monoclonal antibodies developed against those allergenic proteins, in assays for the qualitative and quantitative determination of the levels of the allergenic proteins in natural rubber latex or in products made from latex. Assays for identifying and/or quantitating antibodies in blood or blood products that mediate the occurrence of an allergic reaction induced by natural rubber latex are also provided, together with in vivo and in vitro diagnostic tests for detecting hypersensitivity to natural rubber latex and which involve use of the aforesaid allergenic proteins. The invention also provides for the use of the aforesaid allergens as de-sensitising agents in the treatment of latex protein allergy. There is still further provided a method for removing allergenic proteins from latex products.

Allergenic protein of natural rubber latex of the form with which this invention was refined substantially; They are qualitative measurement and an analysis method for measuring a fixed quantity about the level of the allergenic protein in the product manufactured by the inside of that manufacturing method; and natural rubber latex, or latex, It is related with use of this protein used with the monoclonal antibody generated to these allergenic protein. The antibody in the blood which mediates generating of the allergic reaction induced by natural rubber latex, or blood products Identification and/or an analysis method to quantify, and the anaphylaxis to natural rubber latex is detected and the diagnostic test method besides [which uses said allergenic protein / in the living body and] a living body is also provided. This invention provides use of said allergen as a hypo sensitization agent at the time of treating latex protein allergy. Furthermore, this invention provides the method of removing allergenic protein from a latex product.

The present invention relates to a protein found in natural rubber that can induce an allergic reaction in persons who have been sensitized to it. The invention provides for the process of isolating and purifying the protein and describes the characteristics of the protein, including its molecular weight, isoelectric point, amino acid sequence and allergenicity. The invention also describes the isolation and cloning a the DNA that encodes the protein. The production of the recombinant version of the protein using a protein expression vector is described.

The present invention relates to the isolation of DNA sequences from the Hevea brasiliensis containing the promoter and regulatory region of hevein genes. The promoter sequences of the hevein genes also act as an inducible promoter regulated by wounds and pathogen infection.

The present invention relates to a protein found in natural rubber that can induce an allergic reaction in persons who have been sensitized to it. The invention provides for the process of isolating and purifying the protein and describes the characteristics of the protein, including its molecular weight, isoelectric point, amino acid sequence and allergenicity. The invention also describes the isolation and cloning a the DNA that encodes the protein. The production of the recombinant version of the protein using a protein expression vector is described.

The present invention relates to a protein originating from latex that can
induce an allergic reaction in persons sensitized to the protein. Thus, in a
first aspect, the present invention provides an allergenic latex protein (ALP),
characterized in that the protein has at least 80% sequence identity with SEQ ID
NO 12. The second aspect of the present invention provides for a process for
obtaining a protein or its molecular variant. Further, the invention provides
for a DNA sequence encoding the protein or a portion of the protein and method
for the production of protein or its molecular variants in recombinant form by
inserting the DNA encoding the protein or a variant of the protein into a
appropriate vector and inducing the vector to express recombinant protein or in
recombinant form of the said variant of the protein.

The invention relates to the allergenic latex protein Hev b 4. The full CDNA sequence of the smaller protein components of Hev b 4 is disclosed, together with the amino acid sequence of those components and the synthesis of a recombinant protein using the aforesaid DNA sequence or a synthetic peptide derived from the amino acid sequences. The use of the He b 4 protein complex and of an antibody against that protein is described in immunoassays and in immunotherapy for the relief of allergy or allergy symptoms.

Modified Natural Rubber and the Method for Preparation There Of
Japan JP2007-112937A, appl. 21/10/2005

To provide at a low cost a modified natural rubber having improved properties such as oil resistance and being capable of being used in various uses as a functional material by utilizing as a raw material for modifying the natural rubber vegetable-origin cinnamic acid derivatives and cinnamaldehyde derivatives obtained by decomposing lignin, etc. , heretofore disposed of as wastes. The modified natural rubber is produced by polymerizing vegetable-origin cinnamic acid derivatives and cinnamaldehyde derivatives having polymerizable unsaturations onto a deproteinized natural rubber. It is desirable that the vegetable-origin cinnamic acid derivatives and cinnamaldehyde derivatives optionally together with a vinyl monomer are grafted onto the deproteinized natural rubber.

Apparatus for extracting latex from rubber latex bearing species comprising a housing with a moveable rod wherein a puncture is made in the tree bark using the rod and latex flows through the housing passage and a tubing into a closed container with an air filter. One end of the housing is in the form of a cup of attachment to tree bark. The housing also contains a valve for sealing the housing passage after puncturing. The apparatus is intended for extracting natural rubber field latex that can be processed to give a high quality rubber due to the absence of chemical preservatives and minimal amount of acid used for late coagulation. In addition, the liquid-phase containing the non-rubber components can be obtained in the original form without toxic chemical additives. This permits the production of non-toxic liquid from field latex that contains valuable biochemicals for further exploitation.

This invention relates to allergenic proteins of natural rubber latex in substantially purified form, their production and their use, together with monoclonal antibodies developed against those allergenic proteins, in assays for the qualitative and quantitative determination of the levels of the allergenic proteins in natural rubber latex or in products made from latex. Assays for identifying and/or quantitating antibodies in blood or blood products that mediate the occurrence of an allergic reaction induced by natural rubber latex are also provided, together with in vivo and in vitro diagnostic tests for detecting hypersensitivity to natural rubber latex and which involve use of the aforesaid allergenic proteins. The invention also provides for the use of the aforesaid allergens as de-sensitizing agents in the treatment of latex protein allergy. There is still further provided a method for removing allergenic proteins from latex products.

To provide at a low cost a modified natural rubber having improved properties such as oil resistance and being capable of being used in various uses as a functional material by utilizing as a raw material for modifying the natural rubber vegetable-origin cinnamic acid derivatives and cinnamaldehyde derivatives obtained by decomposing lignin, etc., heretofore disposed of as wastes. The modified natural rubber is produced by polymerizing vegetable-origin cinnamic acid derivatives and cinnamaldehyde derivatives having polymerizable unsaturations onto a deproteinized natural rubber. It is desirable that the vegetable-origin cinnamic acid derivatives and cinnamaldehyde derivatives optionally together with a vinyl monomer are grafted onto the deproteinized natural rubber.

116. DR SITI ARIJA MAD ARIF, CHEW NYU PING AND DR YEANG HOONG YEET

Allergenic Latex Protein
USA 7,732,566, appl. 11/12/2007

The present invention relates to a protein found in natural rubber that can induce an allergic reaction in persons who have been sensitized to it. The invention provides for the process of isolating and purifying the protein and describes the characteristics of the protein, including its molecular weight, isoelectric point, amino acid sequence and allergenicity. The invention also describes the isolation and cloning a the DNA that encodes the protein. The production of the recombinant version of the protein using a protein expression vector is described.

Apparatus for extracting latex from rubber latex bearing species comprising a housing with a moveable rod wherein a puncture is made in the tree bark using the rod and latex flows through the housing passage and a tubing into a closed container with an air filter. One end of the housing is in the form of a cup of attachment to tree bark. The housing also contains a valve for sealing the housing passage after puncturing. The apparatus is intended for extracting natural rubber field latex that can be processed to give a high quality rubber due to the absence of chemical preservatives and minimal amount of acid used for late coagulation. In addition, the liquid-phase containing the non-rubber components can be obtained in the original form without toxic chemical additives. This permits the production of non-toxic liquid from field latex that contains valuable biochemical for further exploitation.

The present invention discloses a process for coating carbon black granules with natural rubber latex to prevent dusting problems. It is therefore an object of the present invention to provide for an alternative process for coating carbon black granules with natural rubber whereby the process does not involve a high reaction temperature.

The present invention relates to a protein found in natural rubber that can induce an allergic reaction in persons who have been sensitized to it. The invention provides for the process of isolating and purifying the protein and describes the characteristics of the protein, including its molecular weight, isoelectric point, amino acid sequence and allergenicity. The invention also describes the isolation and cloning a the DNA that encodes the protein. The production of the recombinant version of the protein using a protein expression vector is described.

The invention relates to the allergenic latex protein Hev b 4. The full CDNA sequence of the smaller protein components of Hev b 4 is disclosed, together with the amino acid sequence of those components and the synthesis of a recombinant protein using the aforesaid DNA sequence or a synthetic peptide derived from the amino acid sequences. The use of the He b 4 protein complex and of an antibody against that protein is described in immunoassays and in immunotherapy for the relief of allergy or allergy symptoms.

This invention is a process for concentrating skim latex by ultra filtration. The ultra filtration system separates the latex free aqueous portion, serum from the latex and subsequently enriches the latex with rubber particles resulting in the increase of the dry rubber or polymer content. The ultra filtration system is used for recovering skim or waste latex with at least 5% dry rubber content.

The present invention relates to a protein found in natural rubber that can induce an allergic reaction in persons who have been sensitized to it. The invention provides for the process of isolating and purifying the protein and describes the characteristics of the protein, including its molecular weight, isoelectric point, amino acid sequence and allergenicity. The invention also describes the isolation and cloning a the DNA that encodes the protein. The production of the recombinant version of the protein using a protein expression vector is described.

This invention is a process for concentrating skim latex by ultra filtration. The ultra filtration system separates the latex free aqueous portion, serum from the latex and subsequently enriches the latex with rubber particles resulting in the increase of the dry rubber or polymer content. The ultra filtration system is used for recovering skim or waste latex with at least 5% dry rubber content.

The present invention is to provide a formulation for making such a tire tread that demonstrates a low rolling and good grip properties and as such is suitable to be used for making all season tire tread.

The present invention relates to a protein found in natural rubber that can induce an allergic reaction in persons who have been sensitized to it. The invention provides for the process of isolating and purifying the protein and describes the characteristics of the protein, including its molecular weight, isoelectric point, amino acid sequence and allergenicity. The invention also describes the isolation and cloning a the DNA that encodes the protein. The production of the recombinant version of the protein using a protein expression vector is described.

The present invention provides a sodium octaborate tetrahydrate preservative system for natural rubber latex, the preservative system contains ammonia or ethanolamine in a range of between 0.2 to 0.3% by weight of latex and sodium octaborate tetrahydrate in a range of between 0.05 to 0.25% by weight.
The present invention consists of several novel features and a combination of parts hereinafter fully described and illustrated in the accompanying description, it being understood that various changes in the details may be made without departing from the scope of the invention or sacrificing any of the advantages of the present invention.

A practical and environmentally-friendly method, i.e. the high temperature-mechanical mixing by using an internal mixing device and a two-roll open milling device is used to produce the carbon blacks-free electrically conductive sulfur-vulcanised rubber blends of solid poly(butadiene-co-acrylonitrile) and solid sulfonic acid doped polyaniline. As a result, they have good potential to be used for manufacturing any antistatic products, electrostatic discharge or dissipative products and electromagnetic or radio frequency interferences shielding products.

The present invention relates to a protein found in natural rubber that can induce an allergic reaction in persons who have been sensitized to it. The invention provides for the process of isolating and purifying the protein and describes the characteristics of the protein, including its molecular weight, isoelectric point, amino acid sequence and allergenicity. The invention also describes the isolation and cloning a the DNA that encodes the protein. The production of the recombinant version of the protein using a protein expression vector is described.

The present invention provides a sodium octaborate tetrahydrate preservative system for natural rubber latex, the preservative system contains ammonia or ethanolamine in a range of between 0.2 to 0.3% by weight of latex and sodium octaborate tetrahydrate in a range of between 0.05 to 0.25% by weight.

The present invention consists of several novel features and a combination of parts hereinafter fully described and illustrated in the accompanying description, it being understood that various changes in the details may be made without departing from the scope of the invention or sacrificing any of the advantages of the present invention.

A practical and environmentally-friendly method, i.e. the high temperature-mechanical mixing by using an internal mixing device and a two-roll open milling device is used to produce the carbon blacks-free electrically conductive sulfur-vulcanised rubber blends of solid poly(butadiene-co-acrylonitrile) and solid sulfonic acid doped polyaniline. As a result, they have good potential to be used for manufacturing any antistatic products, electrostatic discharge or dissipative products and electromagnetic or radio frequency interferences shielding products.